Area Forecast Discussion Issued by NWS Wakefield, VA
000
FXUS61 KAKQ 170101
AFDAKQ
AREA FORECAST DISCUSSION
National Weather Service Wakefield VA
901 PM EDT Sat Mar 16 2024
.SYNOPSIS...
A weak upper level disturbance crosses the area overnight
through early Sunday morning. A cold front will drop through
the region Sunday night bringing in cooler air for the start of
next week. A stronger cold front will cross the area late Monday
into Tuesday morning.
&&
.NEAR TERM /THROUGH 7 am SUNDAY/...
As of 830 PM EDT Saturday...
The latest WX analysis indicates weak sfc high pressure now off
the VA/NC coast, with a weak sfc trough along the coast of SC.
Aloft, the flow is westerly, with a strong shortwave over the
upper midwest, and weaker shortwave energy over the TN Valley,
moving towards the southern Appalachians. The sky is still
mostly clear across the local area, with a light E-SE flow along
the coast, and light/variable to S winds well inland. Temperatures
have dropped off fast since sunset, with most areas ranging
through the 50s (locally some upper 40s over the typically
cooler sections of interior SE VA/NE NC as well as the eastern
shore). Models show the weaker shortwave passing through the
local area late tonight, which will result in an increase in
clouds, especially over the E and SE portions of the FA closer
to the sfc low/trough that is progged to move NE along the
Carolina coast. In addition, some weak elevated instability
(100-300 J/kg MUCAPE and H7-H5 lapse rates of 6.5 to 7C/Km)
will briefly overspread coastal VA/NC late tonight as the
shortwave passes by. As such, a few showers cannot be ruled out
over the Se 1/2 of the CWA between 2-8 AM. Areal average QPFs
are only a few hundredths of an inch. Overnight lows will mostly
range from the upper 40s to the lower 50s.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
As of 225 PM EDT Saturday...
The strong low pressure system tracks east through Quebec Sun into
Mon, sending a second, stronger cold front across the area Sun night-
Mon. Cloud cover will increase throughout the day ahead of the
mainly dry front. However, there may be a little bit of light rain
Sunday evening into early Monday as a weak shortwave also moves
offshore to our south. Will keep PoPs no higher than 20-30% in SE
VA/NE NC with a dry forecast elsewhere. QPFs are a few hundredths of
an inch at best. Sunday will be the warmest day of the next several
with highs in the upper 60s-lower 70s. Cooler air will begin to
filter in behind the boundary, so low temperatures Sunday night
will be in the mid-upper 30s to the west and mid to upper 40s
to the east/near the coast. Breezy/cooler on Mon with widespread
20-25 mph gusts. Forecast highs are in the mid to upper 50s.
A secondary, stronger shot of CAA arrives Monday night-Tuesday
morning as the flow aloft becomes NW. Breezy (especially near the
coast) Monday night with lows in the upper 20s-30s. Tuesday looks to
be the coolest day of the period with continued breezy NW winds
(gusts up to 30 mph possible near the coast) and highs in the mid
50s (except for lower 50s on the MD ern shore).
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
As of 225 PM EDT Saturday...
The flow aloft flattens out a little bit from Wed-Thu, but the
latest (12z) global models and ensembles still show it remaining
WNW. Temperatures moderate into the 60s (with continued dry wx) for
Wed, but may cool back down a bit on Thu behind another dry cold
front. Still breezy out of the WNW on Wed, with lighter N winds
expected on Thu.
Then, attention turns to our next low pressure system, which will
impact the area sometime between Friday night and Sun/Mon. While
there are major differences in the GFS/ECMWF with respect to timing,
ensemble mean precipitation amounts are 0.50-1.50" across the FA
from Friday (3/22) through Monday (3/25). So, will continue to go
with widespread 40-60% PoPs during this time, which will likely need
to be raised as confidence in exact timing increases in the coming
days (given that ensemble mean QPFs are already > 1"in parts of the
area). Temps remain near to below average from Fri through next
weekend.
&&
.AVIATION /01Z SUNDAY THROUGH THURSDAY/...
As of 800 PM EDT Saturday...
VFR through the first part of tonight with light SE winds becoming
SSW overnight. A shortwave crosses the area late tonight, which
may bring a few showers to SBY/PHF/ORF/ECG between 06-12z, with
the highest chc being at ECG/ORF. Flight restrictions, mostly
from MVFR CIGs are expected for a few hrs across SE VA/NE NC and
have included VCSH wording at ORF/ECG for now. VFR after ~13Z
Sunday for all areas with winds shifting to the W-WSW and
increasing to 10-15 kt (w/ gusts to 20 kt).
Outlook: Isolated to widely scattered showers will be possible
over SE terminals (ORF/ECG) with a second, stronger cold front
crossing the region Sun night (which may result in brief flight
restrictions). Otherwise, mainly VFR through the middle of next
week.
&&
.MARINE...
As of 645 PM EDT Saturday...
Brief update to add Small Craft headlines to the Ches Bay and
lower James River this evening into early Sunday. Hi-res
guidance and local wind probs have trended upward with
southerly wind speeds now expected to average 15-20 kt with
gusts to 25 kt over the bay and lower James tonight. Expect SCA
conditions to hold on through 12z/8am for the northern bay zones
while winds farther south should drop below thresholds around
08z/4am. The remainder of the forecast is in good shape.
Previous Discussion as of 200 PM EDT:
Yesterday`s cold front pushed offshore earlier this morning,
allowing weak high pressure to build in behind it. Latest obs
indicate the development of a seabreeze with wind speeds at 5-10kt.
Seas are 2-3ft and waves are around 1ft (2ft in the mouth of the
bay). High pressure will slide offshore to the SE this evening as
another (dry) cold front approaches the region. Behind the high,
winds become SE at 10-15kt, then increasing to 15-18kt (highest in
northern waters) as they turn to the SW late tonight. Breezier
Sunday, but still sub-SCA with westerly winds at ~10kt with gusts to
15kt.
W-SW winds turn N-NW, increasing late Sunday night/Monday morning in
tightening pressure gradient ahead of the next frontal passage. Once
again, this surge is forecast to brief enough to hold off with any
headlines despite a few gusts to ~20kt (reasonable to think a brief
Marine Statement may be needed during this period). However, SCA
headlines are likely to be needed as early as Monday evening, but
especially late Monday night/ early Tuesday. A strong cold front
crosses the region during this period, with strong cold air
advection expected. EPS/GEFS both show 850mb temperatures dropping
to as low as -8C to -10C by 12Z Tuesday. Wind probs are low for
prolonged gale force gusts (single digit probs), but solid SCAs
appear likely during this timeframe. Winds slowly diminish Tuesday
with SCA potentially coming down Tuesday afternoon. Winds back to to
W-SW winds late Tue into Wed, with potential for a brief period
of SCA conditions Tue night in the lower bay and lower James
River.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...None.
NC...None.
VA...None.
MARINE...Small Craft Advisory until 7 AM EDT Sunday for ANZ630-631.
Small Craft Advisory until 4 AM EDT Sunday for ANZ632-634-638.
&&
$$
SYNOPSIS...TMG
NEAR TERM...ERI/LKB
SHORT TERM...ERI/TMG
LONG TERM...ERI/TMG
AVIATION...ERI/LKB
MARINE...AM/RHR